[AS3] Compilation Error

I’m trying my hardest to understand ActionScript 3, and I follow the tutorials all well and good, but when it comes to creating my own files, I keep hitting this error when compiling:

TypeError: Error #1007: Instantiation attempted on a non-constructor.
at Main$iinit()

What on earth does it mean? what have I done wrong? my Main.as code is as follows:

package {
    import flash.display.*;
    import flash.events.Event;
    import flash.events.MouseEvent;
    import flash.ui.Mouse;
    public class Main extends MovieClip {
        private var cursorA:MovieClip = new MovieClip();
        public function Main() {
            cursorA = new cursorA();
            stage.addEventListener(Event.MOUSE_LEAVE, cursorHide);
            stage.addEventListener(MouseEvent.MOUSE_MOVE, cursorFollow);
        public function cursorHide(evt:Event):void {
            cursorA.visible = false;
        public function cursorFollow(evt:MouseEvent):void {
            if (!cursor.visible) cursorA.visible = true;
            cursorA.x = stage.mouseX;
            cursorA.y = stage.mouseY;

I’ve got 2 movieclips in the library, and i’ve the linkage stuff (only referred to cursorA in the class though)